Monocular head mounted display systems are known such as shown in Furness et al. U.S. Pat. No. 5,162,828 and Heacock et al. U.S. Pat. No. 5,539,422. In these systems a display and an associated optical system are mounted on a frame relative to either a user's right eye or left eye so that the user can view, with one eye, an enlarged image that appears at a distance from the user that is greater than the optical path from the display to the user's eye. However, most people are either right eye dominant or left eye dominant. A right dominant person has trouble viewing an image projected only in front of his left eye. Similarly, a left eye dominant person has trouble viewing an image projected only in front of his right eye. As such, a right eye display system is preferable for a right eye dominant person and a left eye display system is preferable for a left eye dominant person. Because the display is typically mounted in a fixed position on the frame relative to a single image viewing eye in known head mounted display systems, one system cannot typically be used by both right eye and left eye dominant users.